def chisl(s):
    k=" "
    if s == "zero": k="0"
    elif s == "one": k="1"
    elif s == "otwo": k="2"
    elif s == "three": k="3"
    elif s == "ofour": k="4"
    elif s == "ofive": k="5"
    elif s == "six": k="6"
    elif s == "oseven": k="7"
    elif s == "eight": k="8"
    elif s == "nine": k="9"
    else: return 0
    return k
prost = [101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 657, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997]
try:

s1, s2, s3 = input().split()
a1, a2= 0,0
num = int(chisl(s1)+chisl(s2)+chisl(3))

for x in range(len(prost)):
    if prost[x]>num:
        a2 = x
        a1 = x-1
    break

if abs(prost[a1]-num)<prost[a2]:
    print(prost[a2])
elif abs(prost[a1]-num)<=prost[a2] - num:
    print(prost[a1])
except:
    print("wrong input")